Various diseases may be treated by localized delivery of a therapeutic agent to an internal portion of a patient's body. For example, atherosclerotic disease, which is characterized by the build-up of plaque on the interior wall of an arterial vessel, may be treated by applying a therapeutic agent, such as heparin, to the diseased portion of a vessel wall. However, delivery and application of the therapeutic agent directly to the vessel wall may be complicated by the constant flow of blood through the vessel, which tends to carry the therapeutic agent downstream, away from the diseased tissue. Thus, a need exists for a device capable of effective localized delivery and application of a therapeutic agent to an internal portion of a patient's body, especially to the internal surface of a vessel or lumen.
Information relevant to attempts at addressing this or related needs can be found in such references as U.S. Pat. No. 5,868,719 to Tsukernik and U.S. Pat. No. 6,050,930 to Teirstein, each of which is incorporated by reference in its entirety herein. However, prior attempts at providing effective agent delivery devices suffer from certain disadvantages.
For example, prior devices may be limited in agent delivery capacity because they employ pre-loaded agent delivery members, such as partially or fully impregnated sponge bodies, to deliver a finite amount of agent to a body lumen. Such agent delivery members are impregnated with a therapeutic agent prior to a vessel treatment procedure and carry only a pre-determined amount of agent to a target region. Thus, a need exists for a device capable of delivering and applying a replenishable, active source of therapeutic agent to a body lumen.
In addition, prior devices may require the exertion of significant pressure upon a lumen wall, as with an inflatable member, to force a therapeutic agent from an agent delivery member impregnated with the therapeutic agent to the surface of a lumen wall. Thus, a need exists for a device capable of delivering and applying a therapeutic agent to the wall of a body lumen without the exertion of significant pressure upon the lumen wall.
A need further exists for a device capable of delivering and applying a therapeutic agent to a lumen wall in a controlled and uniform fashion. Moreover, a need exists for an agent delivery device designed to maximize the amount of agent actually applied to and absorbed by a lumen wall, while minimizing the amount of agent released from the device without being applied to or absorbed by the lumen wall. These and other objectives are accomplished by the present invention.